This is some info i could retrieve from wikipedia. Fog is a cloud bank that is in contact with the ground. A cloud may be considered partly fog; for example, the part of a cloud that is suspended in the air above the ground is not considered fog, whereas the part of the cloud that comes in contact with higher ground is considered fog. Fog is distinguished from mist only by its density, as expressed in the resulting decrease in visibility: Fog reduces visibility to less than 1 km, whereas mist reduces visibility to no less than 2 km.
What the fog?! Here are some pics I took around town today (Monday) at Jalan kebun Klang. The worst so far... Poor for those who stay nearby as they stay around the megahaze!